Fence Post Depth
Find how deep to bury a fence post and its concrete.
About Fence Post Depth
A post should be buried below the frost line and at least a third of its exposed height. The concrete volume is the filled hole volume holding that buried portion. Burying below the frost line prevents frost heave, and the third-of-height rule keeps the post stable under wind load.
Formula
Fence Post Depth
Buried depth = max(frost line, post height / 3)
- frost line
- How deep the ground freezes in winter
Worked example
With the default values below, Fence Post Depth returns Buried Depth of 2.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Post above ground
- 6 ft
- Frost line
- 2 ft
- Hole diameterminimum 1 in
- 10 in
Results
- Buried Depth
- 2.00 ft
- Concrete per Post
- 1.09 cu ft
- Bags per Post
- 2.4 60 lb bags
Step by step
- 1Values used
- 2Fence Post Depth
- 3Buried Depth= 2.00 ft
- 4Concrete per Post= 1.09 cu ft
- 5Bags per Post= 2.4 60 lb bags
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Fence Post Depth calculated?
Buried depth = max(frost line, post height / 3) A post should be buried below the frost line and at least a third of its exposed height. The concrete volume is the filled hole volume holding that buried portion.
Why does Fence Post Depth matter?
Burying below the frost line prevents frost heave, and the third-of-height rule keeps the post stable under wind load.
What values do I need to enter?
This calculator takes 3 inputs: Post above ground, Frost line, Hole diameter. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.